<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2016 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: 流年 <liu21st@gmail.com>
// +----------------------------------------------------------------------

// 应用公共文件
function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=false)
{

    if (function_exists("mb_substr")) {

        if ($suffix)

            return mb_substr($str, $start, $length, $charset) . "...";

        else

            return mb_substr($str, $start, $length, $charset);

    } elseif (function_exists('iconv_substr')) {

        if ($suffix)

            return iconv_substr($str, $start, $length, $charset) . "...";

        else

            return iconv_substr($str, $start, $length, $charset);

    }

    $re['utf-8'] = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef][x80-xbf]{2}|[xf0-xff][x80-xbf]{3}/";

    $re['gb2312'] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/";

    $re['gbk'] = "/[x01-x7f]|[x81-xfe][x40-xfe]/";

    $re['big5'] = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/";

    preg_match_all($re[$charset], $str, $match);

    $slice = join("", array_slice($match[0], $start, $length));

    if ($suffix) return $slice . "…";

    return $slice;

}
